The Chaos Giant is a dangerous entity created by the Red Axe. It looks like a regular giant, except its left arm is extremely large and spined, its right arm has made place for three smaller arms wielding Dragon throwing axes, and it has some sort of chaos device covering its head and neck. It is known for dropping the axes it uses in battle, as well as Dragon pickaxes.

They can be found in a cave at the end of the Barendir Caves and are in a small, packed room. They can only be fought after Birthright of the Dwarves is completed. They can be found by entering the Keldagrim tunnels from the Fremennik Province, and running east once inside the first mine section, to the tunnel guarded by a Black Guard. Following that tunnel to the end leads to the cave where the Chaos Giants are located.

Upon release, killing these would count towards fire giant slayer tasks. This was fixed in a silent patch within a week of release. On 11 April2016, they became a separate category of their own, assigned by Kuradal and Morvran.

This is the first player-designed monster in Runescape.

On 19 November2013 they received an overhaul to their drop table, removing most of the "junk" and replacing it with better items.